Siemens SIMATIC S5 Manual page 78

2 Engineering
2.8.3 Communication program SIMATIC S5
Overview
The following blocks contain the communication program of the S5-CPU. In this
scenario, the S5 sends and receives data via a passive ISO-on-TCP connection.
The connection is established from the S7-1500 CPU.
OB 21
Startup
OB 22
Startup
OB 1
Main
Function
Via the connection actively established by the S7-1500 CPU, data are sent
bidirectionally with a count value from the SIMATIC S5 to the S7-1500 every
second. From there, this count value is mirrored and sent back. After the data have
been received, this count value is increased by +1 and sent again.
In case of the SIMATIC S5 CPU being restarted, a deletion identifier is sent and
the count value is reset.
Description of the blocks
The following blocks contain the communication program of the S5-CPU.
Table 2-23
Block
OB 21
OB 22
OB 1
FB 35
Ethernet Communication (ISO on TCP) between SIMATIC S5 and
SIMATIC S7-1500 Controllers
Entry-ID: 109482475, V1.2,
FB35
SEND_ALL
User
blocks
Symbol
Startup_OB21
Startup_OB22
Main
ID6_S7
07/2019
HTB
SYNCHRON
HTB SEND
SEND_DB
HTB RECV
HTB
HTB
RECV_ALL
Handling Data blocks
blocks
Description
Startup OB (restart/warm start)
Startup OB (network/cold start)
User program call of FB 33 and of the HTBs
SEND/RECEIVE ALL
Time-triggered call of the send and receive
functions via S5 handling blocks (HTBs).
Increase of count value in the data
RECV_DB
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